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genetic code and regulation

...is called a poly(A) tail, which is characteristic of all eukaryotic DNA. At the 5′ end of the mRNA, a modified guanine nucleotide, called a cap, is added. Noncoding nucleotide sequences called
introns are excised from the RNA at this stage in a process called
intron splicing. Molecular complexes called spliceosomes, which are composed of proteins and RNA, have RNA sequences that are...

processing of mRNA

...revealed that portions of newly synthesized RNA molecules are cut out and discarded. In many genes, the regions coding for proteins are interrupted by intervening sequences of nucleotides called
introns. These
introns must be excised from the RNA copy before it can be released from the nucleus as a functional mRNA. The number and size of
introns within a gene vary greatly, from no
introns at...

RNA splicing

...article) and Phillip A. Sharp, whose work won them a Nobel Prize in 1993. The segments of DNA or RNA coding for protein are called exons, and the noncoding regions separating the exons are called
introns. Following transcription, these coding sequences must be joined together before the mRNAs can function. The process of removal of the
introns and subsequent rejoining of the exons is called...

work of

Fire

...Institute of Technology (MIT), where he worked with American molecular biologist Philip A. Sharp, who was awarded the 1993 Nobel Prize for Physiology or Medicine for his independent discovery of
introns—long sections of DNA that do not encode proteins but are located within genes. Fire received a Ph.D. in biology from MIT in 1983 and then went to Cambridge, Eng., joining the Medical...

Roberts

...the segments of DNA that code for proteins are interrupted by lengthy stretches of DNA that do not contain genetic information. The coding segments are called exons; the noncoding ones are called
introns. A research team working under Sharp at the Massachusetts Institute of Technology produced the same finding that same year. Previously, based on studies of bacterial DNA, biologists believed...

Sharp

...corresponded to four separate, discontinuous segments of DNA. They found that the segments of DNA that coded for proteins, now called exons, were separated by long stretches of DNA, now called
introns, that did not contain genetic information. At the same time, a team working independently under Roberts came up with the same finding. Previously biologists had believed that genes were...